关于a13a1a3a521的百科

• 已知等比数列{an}满足a1=3,a1+a3+a5=21,则a3+a5+a7=           （  ） ...

• 问题详情：已知等比数列{an}满足a1=3,a1+a3+a5=21,则a3+a5+a7=           （  ）                                    A.21          B.42         C.63             D.84【回答】B知识点：...
• 2022-08-127435